Core cleaner



E. B. ESTERS CORE CLEANER s Sheets-Shet 1 Filed Jan. 22, 1951 Ernie Byron Esters WWW Aug. 11, 1953 E. B. ESTERS 2,648,170

CORE CLEANER Filed Jan. 22, 1951 s Sheets-Sheet s Fig. 5. I0 20 56 226 4 l @40 30 34 228 =31 44 a; f L...

Fig. 6. /0 I46 Inventor I32 I38 3 v Ernie Byron Esters wi away fiMe Patented Aug. 11 1953 CORE CLEANER -eEm s -lix on Este Hi hla d th-Mich- 9:0la m 1 This invention comprises novel and useful-improvements incoreacleaning devices-and more particulary pertains-to adevice-"for abr-ading the 1 rough-projections f'romthecore.

zAn important object of this invention isi-to provide a -device --for cleaning z the rough projections; on each of the faces {of the-core --reduce the core to-proper dimensions to'thereby produce v a-smoother and moreuniform core.

-Another object of this invention-is to-- provide a-device-whichwi1l simultaneously remove the projections on the faces and edges ofythe core while-removing the;-projections-in the openings formed in thecore.

I A further -bject--0f this invention is to A pro- .:..vide a -devicefon cleaning'cores, in: accordance with theforegoingobj ects,'-= which device will automatically: stop after- -thecyc1e- -of olea'ning g operations oneachcorehas been-completed.

An important feature of this invention resides inthe provision 0f a-core support, a -reamer sup @port. mounted for movement relative to said core support, rotatable 'reamers carried byx-the reamer msupports for movement. i-therewith towards: and :rawayfrom the core carried iby ithezcorei support, with -.means. for-driving: the-.reamers aandsmoving ithereamer-support, andamechanism for cyclicalzily connecting rand: disconnecting-the reamer gsupport moving means from the: -driving.-means.

Another feature of this inventionresides in the provision 'of acore ;cleaner,--in1 accordance with \theforegoing feature, with'abrading plates carried by'thereamer supports-for. movement therewith into and out ofengagementiwithithe-iedge of a core carried. by the core-support toiremove therough projections from, theedges f the-core.

A further-feature of this invention resides-in the provisionof v a-core cleaner, inaccordance ,with theforegoingfeatures;v with a cover for the score, support, and abrading bars carriedbythe vcover, together with a. mechanism reciprocating" Hthe. .abradingi bars in response to movement of thevreamer support, toremove rough, projections fromthe face of .the core.

.Yet another feature of this invention resides inthe. provision of a core cleaner, in aficordance" with the foregoing features, with acIutchmechas nism for selectively. establishing, a dri i pen... n ection between a prime mover and the vreamer i support moving means, and amechanism responsive to theclosing of thecoverfor establishing" driving connection between the members of the clutch mechanism, together with a mechanism responsive to the completionpf the cycle of opera- 'tion'of the core cleaner for selectively disconnfict ing theclutch mechanism.

i' se rm 2 Theseetogether with various ancillarvgobjeets =-andfeatures are attained byzthis device, as pre- 1 ferredtembodiment of which has been illustrated rby way ofrexample I only in. ,the accompanying l 1 drawingswherein: V

F1Jg ure leis. a verticalcsectionalview, ta ithetplane l-l of 'Figure 2;

i Eigure 2 is a top' plan zviewiofzthe coretcleaner; -Figure 3v is a transverse. verticallsectionaLiview 1 a takenl on the plane 3:--3; of l'ligure 1;

sFigure 4. is a transverse.-lverticaljsectional @view takenlonithe plane 4s.:4 of. -Fig'ure '1;

Figure; 5 is a horizontal sectional views-taken ion thelplane' 5+5 of: Figure 1; Figure 6 is a horizontalcsectional-:vievvrtaken onvthe-plane 6--6 of -Figure 1; i c

:Figure 'lis airagmentaryisectional view.- ofvithe l t-clutch i mechanism;- :taken on a the :plane 1 :1 of -:Eigure 6; iEigure 8 is axfragmentary transverse sectional iew of theclutchmechanism; taken .on theaplane .'::8Hof eFig-urewl; & v s'Figure 9.-.is a diagrammaticlviewflof therco c-systemlfor the corecleaner; and Figure; 10 is. a; perspective;:elevational; vieweof i .onetype pfpore which the core pleaner is-ladapted 9.170 cleanse.

:Reference-ris lnowamadegsmorespecifically to-the o-ac omp nyin drawings :where kthec reieleaner,

enoted rsenenal yvbyc the.1-1.1.maera1 d t- 5131 1115- rat d-rami -which \ooreiclean p. includes ateom A .rivin z-meoh nismr a-ream r: movmame h m 4, a a i ad'1 :m chanis "J6 actuated-1 m r m inamesha ism fo l ,v .T't ej5QI ;an an a rad n i us em m fizs a ried a s h em s: movement therewith, into -an out mom w l-it eiedg l a he o nea-$91 rou p pie ltions-t r imm- 40 1.11 esoreeclean lfli nc ud s r v amethavin a le: irons nda ds?! lwh hstand ms. rt

kenwn I ntrol en a move the sett r ltte niu b n nd ll v an e on lts delra s Zrandren rai s 2 34 (1- ,atl t i r l,

sen b th ;fiangedcmpt nr oi iins.-ma es"- A core supporting plate '28 sv. .seou redto the H st ndards? t r ia e th n: en t ,ri s. atnlur i yr f. ward oextend sl ore supsn rt Qs sJ-l w ich aresec r' o it ma e.

i ,a ib l tene sfi .Each o l etnos w haste 0 e tens on; ut i ead d i attac dwithe mhh ;h@a s.35- nl tensionlbei jo med o s ,b sirec r b l n-. d, nr ssiq wh h a lmo'ld M n .th gcq OWiQil lm,ihap atali may temiiv e with anlura i pf ap rtures orem tlth -;shJ1i a' .lp s tiqai s t e,pos s-iwctotsorr spond to the recesses inthe'core being worked 3 upon so as to support and center the core and, alternatively, if the core does not have depressions therein, it will be appreciated that the posts may be utilized to merely support the core.

A reamer support plate 38 is provided with openings 40 therein for guidably receiving the posts 30, angle iron end bars 42 being secured to the standards 20, below the end rails 24, to limit downward movement of the reamer support plate. Guide rails 44 are secured between the end rails 24 and the end bars 42 and are guidably received in notches 46 in the reamer support plate 38 to guide vertical reciprocatory movement of the latter. A plurality of flanged journals 48 are adjustably secured to the reamer support plate 38, as by fasteners 50 which extend through slots 62 in the plate 38, each of which journals rotatably receives a reamer spindle 54. A suitable reamer 56 is carried by the upper end of each spindle 54, and a bevel gear 58 is non-rotatably secured to the lower end of each spindle. The bevel gears 58 are in mesh engagement with complementary bevel gears 60 disposed on shafts 62, the latter being rotatably journaled in brackets 64 and 66, carried by the undersurface of the reamer mounting plate 38. A plate 68 connects the lower ends of the adjacent brackets 66, and provides a journal for the shaft I having the pinion I2 thereon, which pinion is adapted to drivingly engage the bevel gears I4 on the registering ends of the shafts 62. Although a suitable gear drive for the reamers has been described, it is to be understood that a belt or chain drive could be substituted without departing from the spirit of the invention.

In order to drive the pinion I2 carried by the shaft I0, there is provided an electric motor 16 which is secured by fasteners I8 to the motor mounting plate 26. The motor pulley 80 is connected by means of a belt 82 to a pulley 84 mounted on the main drive shaft 86. As is best shown in Figures 1 and 3, the shaft 86 is rotatably carried by journals 88 on the transverse angle iron braces 80 on the standards 20. A bevel gear 82 is non-rotatably disposed on the shaft 86 in meshing engagement with the bevel gear 84 on the vertically disposed reamer drive shaft 86, the shaft 86 being journaled in the bracket 98 carried by the side bars I00. The shaft 96 is provided with an internally splined socket I02 which receives the complementarily splined end I04 of the shaft I0, to thereby provide a longitudinally extensible coupling for the shafts. I

The reamer moving mechanism I4 includes a cam shaft I06 rotatably disposed in journals I08 on cross members I I0, and cam member I I2 carried by the cam shaft.

Cam followers H4 are secured to the reamer mounting plate 38 and reciprocably extend through sleeves I I 6 on the core support plate 28, into engagement with the cam members II2. Thus, as the shaft I06 is rotated the reamer support plate 38 is vertically reciprocated whereby the reamers will be moved into and out of the bores in the core I I8.

A clutch mechanism I 20 is disposed on the cam shaft I06 and includes a first clutch member I22 rotatably mounted on the shaft I06 and having a pulley I24 secured thereto. A collar I26 is fixedly secured to the shaft I06 and engages the first clutch member to limit axial movement thereof, and a belt I28 is disposed about the pulley I24 and the pulley I30 on the main drive shaft 86, to drivingly connect the clutch mechanism to the motor I6. A second clutch member I32 is splined to the shaft I06, as at I34 for sliding, but non-rotating movement thereon, and a compression spring I36 is disposed in the counterbore I38 in the second clutch member, which spring otherwise engages the cap member I40 which is fixed to the shaft I06, to thereby yieldingly urge the second clutch member into engagement with the first clutch member. As is shown in Figure 7, a collar I42 is carried by the cap to guide the spring and second clutch member as the latter is shifted axially on the shaft I 06. A brace bracket I44 is secured to a mounting rail I46, to support the cam shaft intermediate its ends.

In order to move the clutch members into and out of engagement, the second clutch member I32 is provided with a peripheral cam surface I48 which is so constructed as to shift the second cam member axially on the shaft in opposition to the spring I36, when the vertically reciprocable, and laterally inflexible cam follower I50 engages the cam surface. As is best shown in Figures 1 and 9, the follower I50 is slidably and non-rotatably received in an internally splined sleeve I52 carried by the core support plate 28, and is provided with rack teeth I64 which mesh with a spur gear I56. The spur gear I56 is non-rotatably mounted on the stub shaft I58, which is journaled in bearing plates I60 and an arm I62 is fixedly secured to the stub shaft. The arm I62 is normally biased in a clockwise direction, as viewed in Figures 1 and 9, by-a spring I64, whereby the follower I50 is normally urged into its cam engaging position. A solenoid I66 having a reciprocable plunger I68 actuated thereby, is provided to selectively move the follower I50 out of cam engaging position, the plunger being suitably pivoted to the arm I62. Thus, when the follower I50 is moved out of engagement with the cam surface I48, the clutch members will be moved into driving engagement by the spring I36, whereby the cam members I I2 will be rotated by the motor I6, to reci rocate the reamer mounting plate 38. Conversely, when the follower I50 is disposed in engagement with the cam surface, the second clutch member is moved axially on the cam shaft I06 out of engagement with the first clutch member, as the second clutch member rotates.

The abrading mechanism I6 includes a cover II0 which is hingedly attached, as at II2, to one of the side rails 22, and a handle II4, to facilitate opening and closing of the cover. As is best shown in Figure 2, the cover is provided with a plurality of openings II6 for the reception of the projecting bosses I18 on the core II8. Obviously, the spacing of the openings will be regulated by the positioning of the bosses on the particular core and, if no bosses are utilized, the abrading bars, to be described hereinafter, may be mounted on the undersurface of the cover to smooth the face of the core. The abrading bars I80, I82 and I84, shown in the accompanying drawing, have abrading blocks I86 thereon, each of which blocks overlies one of the openings I16. An actuator arm I88 is pivotally attached, intermediate its ends as at I90, to the cover I10, and has one end pivotally connected by the pin I92 to the bar I80. An actuator link I84 is terminally pivoted as at I96 and I98 to the bars I and I82, and pivotally attached by the pin 200 to the cover. A second link 202 is pivoted by pin 204 to the cover, and terminally pivoted as at 206 and 208 to the links I80 and I84. It will thus be noted that as the actuator arm I88 is pivoted fiaeasymo 5 about the' pivot poi-nt 1 90; the -bars' i 80 I82 and 1 8hwill bemoved longitiidinally. Obviously, by -varying the 'relative -positionot'the. pivots, :the oaimount of movement'may-beregulated. Further, since the bars :wiu tend 'tomove' in arcs about the e pivot points ofthe linkswhich are att'achedthereto, it will be-appreciated that a loose pivotal' con- I- nection between the: links and bars'must be provided to :permit movementp'of. the :bars and links withoutwbinding. filherbars' 'l 821ia'nd. =1 84 may be 5 suitably-guidedniniany desiredmanner, if-..desired .zitoj constrain movement of the :bars: to a predeterrmined: path; and fonthis-purposerthe bars] 84 may nb'e providedwithaanelongated slot-:2 I which slidniablyueceives. a'irpivlotutpin 2| 2 which. is. slidably ;i..disposectin aislot2| vlizirrthe:a'etuatorarm.j Obvirouslygthe slot: 2 l tmaywbe; dimensioned so as i130 1:1;,constrains-iwithine;"prescrihed iziimits, ;;;the move- -:.-ment :ofxthe: bar rite-transverse f its: longitudinal i'EJaXIS.

; 1,- A bellrrcrank "2 I 6,; is vertically pivotally' mounted a :on the bracket Z IB-carried by the side'rai122, and xhas; .one arm thereof connected by link i 220 to the I :reamer supp-ortvpla'te: 38, .the other arm being receivedimthe yoke=222-on the end of the actua- I storrarm'clfie, whereby the-=bellcrank will be ver- --,tica lly pivoted; as the'reamer plate is vertically w oscillated to thereby reciprocate the abrading mbarsiithrough the intermediary of the actuator arm-4 8 8 1The..-abrad-ing1 assembly It! includes a plurality a-of Z-shaped- -brackets 224," one leg of each of lwhichfis secured tothe reamer support plate 38, as byiasteners'ZZ 6, the other leg of-which brackt ets vertically pivotally support the-abrading memfibers 228. u A. spr-ing-230,is interposed between the abradingimembers andthe Z-shaped bracket to which they are attached to yieldingly-urgethe ,members, .into. core,. engaging position. As is thought. apparent, the size and shape of the wabrading members, ands-their relative positioning won .the reamer, rsupportwplate V will besdependent .,-uponithe .shape. of the core and. the complexity of. theiorm of the edges.

.ltis contemplated that/the control of .the engagementcof the .clutchimembers be regulated, in responsetosthe closing of the coverji'm, and for lthis purpose; there. is provided a switch 232 which -is electrically-connected in ,series with the sole- I now 'fl"66,. and whichs'witcli is closed in response to closing of the cover" ['10 and.yielding1y biased open, in any desired mannenwhen the cover is opened, 'Additionally', there is provided a cam [operatedswitch"234 which is electrically connected in series with the switch'232 and the source "'of power (not shown) .1 The switch 234 is con- .istructed so as to remain in either open or closed position, dependent on the manner in which it is set. A cam 236 is carried by the cam shaftl'06,

and a follower rod 238 rides on the cam 236 to selectively move the switch 234.110 its open posi- "tion when the lobeon'the cam 236 elevates the rod.

The motor 16 is connectedto the source of power-and the master switch 240, 'by conductors "242and 244.

In operation, the'switch 234 is first manually closed; prior to closing of thecover' llfl, so that whenthe cover isclosectthe switch 232 will also be closedgthereby energizing-the solenoid to retractthe follower I50. It maybe noted, however,

that the switches 2-32 and" 234 may be'consolirelated if'there isprovided a finger on the cover *a'which will releasably engagethe'composite switch 11' toimove. itrinto itsclosed positionwhen the cover w-iszclosed, and which finger will release the switch 6 te-permit the sam'e'to-be-opened; and-v rem'ainaepen, 1 by meansof the tollower rod -2'3 8Wheri theglatter is=vertically=oseillated.

Whem the'= follower I SII- -is -.retractedw gandz izthe clutch members 22 nand 't32;moved intozzdriving engagementfthe shaft 106 yandlcam members :I. l 2 thereon': willa sbe'srotated-to :vertieally ios'cillate ;the uni-reamerisupportz platei3 fl-aa-ndithe xreamers-narried thereby, into and out ottthe:bores-inatheuxore 5.118. cm this :regardu it=v iszto :be; noted: thatzthe :reamers are'ubeing :rotatedyrwhilerbeing yerticallysosoilzol'ated;.; iby meansirof lthe;:extensible:v coupling-abeartweensthershaftsi Strand) 'lO- :which zrdrivesrrthe :.-.reamer.:.:drive.= shaftizfl. sAs the; reamenzsupport plate: is vertically:oscillated athe; abrading, mem- U hers 8-;wi1lrengagethei dges-of the core l lt8-ion '-,t,=the =posts 30,5.t0aSIllOOth theiedges; and the abradoingabars 11:80, pl 82 -.-and-:i'l-84?-will; be rmovedglongb i-:tudinally to cause-the blocks 1-86 =to smooth the ubosses ,4 8,1;by; means of the :hell crank ZlBvWhiCh sis pivoted in: response to verticalv oscillationof 1' rthe-reamensupport plate,"in a manner; previously described. I

' =Theicam 2-,3siisrsoishaped to, s'cause the switch :92-34.:t0 biz-opened; a. predetermined time-before the ereamersahave: been retracted from therbores in 1* the core, and the abrading members, .moved .-.-out I of. engagement.- with -the edges of the core, so that .the follower- 450,will.-beibiased ,bysthe espring .IM intocamtsurface engagingmosition.

Obviously, the .cam surface 4 48,-.and'thecam 236 must besouarranged. that theiclutchmembers will be disconnectediafter the .reamershave been smovedoutofithe bores. in thecore.

.-Having described the invention, what is claimed "asnewis: t

1. vA core. cleaningmachine..comprisinga supporting structure. including i 2. core support, a ,1 reamer .support mounted a on, said supporting structure. iorimovementrelative to--said core .sup-

. porttowardspanduaway irom. a 3 core. carried,;by I thelatter, a reamer-rotatably mounted on said .reamersupport for movement about an. axis .par- .tallel tothe direction of movement of the reamer 1 support; means connected to :the reamer ;for,.,.ro- .:i'tating the same, means ,COIHIBCtBdn-tO thev reamer mSllDDOIt forrmoving the 1 same;- drivermeans'tqconnected to said reamer rotatinggmeans :andtsaid -1 ,wreamer' support moving; means; andimeans selec- 1'; ively; ,connectingtrsaid' reamer supportarmoving ':.::means"- with saidr v:driving is'means xfor: cyclically .:driving.' rsaidir reamer: :support moving 4' means, -oabrading means mounted for-"movement trans- .iverseitheq directionof movement of said reamer support means for removing pr oj ections 'on a core carried 'by said core supporting means, andmeans responsive to movement of said reamer support -'-,;meansfor moving said abrading means.

2: A corecleaningmetchine comprising a sunporting structure including a *core support;v a .-.reamer support mounted: 'on'- I said supporting structurefor movementrelativ'e to said core sup- .,port-etoward uandtzaway =froma core carried {by the :latter, a :treamer rotatably mounted on "said 5 reamer supportfor movement about an axis aparallel to the direction of movement of the reamer support; means connected to' the reamerzfor :roatating 'the same/means "connected to the reamer support for :moving' the same, drive means con- 7mnected to said \reamer rotating 'means and "said reamer support moving means, and means selectively connecting said reamer support i -moving means with said "driving "means for. r cyclically :itdrivingm said reamer support :moving means, ;iabradingtmeansl mounted:for movement transverse the direction of movement of said reamer support means for removing projections on a core carried by said core supporting means, and means responsive to movement of said reamer support means for moving said abrading means, a second abrading means carried by said reamer support mean for movement therewith into and out of engagement with the edge of a core positioned on said core support means.

3. A core cleaning machine comprising a supporting structure including a core support, a reamer support mounted on said supporting structure for movement relative to said core support towards and away from a core carried by the latter, a reamer rotatably mounted on said reamer support for movement about an axis parallel to the direction of movement of the reamer support, means connected to the reamer for rotating the same, means connected to the reamer support for moving the same, drive means connected to said reamer rotating means and said reamer support moving means, a cover for said core support carried by said supporting structure, linkage movable by the closing of said cover for drivingly connecting said reamer support moving means to said driving means, means operatively connected to said reamer support moving means for cyclically disconnecting said drive means from said reamer support moving means, means carried by said cover for abrading the face of core carried by said core support, and means responsive to movement of said reamer support means for moving said abrading means.

4. A core cleaning machine comprising a supporting structure including a core support, a reamer support mounted on said supporting structure for movement relative to said core support towards and away from a core carried by the latter, a reamer rotatably mounted on said reamer support for movement about an axis parallel to the direction'of movement of the reamer support, means connected to the reamer for rotating the same, means connected to the reamer support for moving the same, drive means connected to said reamer rotating means and said a reamer support moving means, a cover for said core support carried by said supporting structure, linkage movable by the closing of said cover for drivingly connecting said reamer support moving means to said driving means, means operatively connected to said reamer support moving means for cyclically disconnecting said drive means from said reamer support moving means, abrading means carried by said reamer support means for movement therewith into and out of engagement with the edge of the core carried by said' core support.

5. A core cleaning machine comprising a supporting structure including a core support, a reamer support mounted on said supporting structure for movement relative to said core support towards and away from a core carried by the latter, a reamer rotatably mounted on said reamer support for movement about an axis parallel to the direction of movement of the reamer support, means connected to the reamer for rotating the same, means connected to the reamer support for moving the same, drive means connected to said reamer rotating means and said reamer support moving means, a cover for said core support carried by said supporting structure, linkage movable by the closing of said cover for drivingly connecting said reamer support moving means to said driving means, means operatively connected to said reamer support moving means for cyclically disconnecting said drive means from said reamer support moving means, means carried by said cover for abrading the face of core carried by said core support, and linkage connected to and actuated by movement of said reamer support means for moving said abrading means, a second abrading means carried by said reamer support means for movement therewith into and out of engagement with the edge of a core carried by said core support means.

6. A core cleaning machine comprising a supporting structure including a core support, a reamer support mounted on said supporting structure for movement relative to said core support towards and away from a core carried by the latter, a reamer rotatably mounted on said reamer support for movement about an axis parallel to the direction of movement of the reamer support, means connected to the reamer for rotating the same, means connected to the reamer support for moving the same, drive means connected to said reamer rotating means and said reamer support moving means, clutch means including first and second relatively movable members, said drive means being operatively connected to said first member, cam means carried by one of said members, a retractible follower engaging with said cam means for selectively moving said clutch members out of driving engagement with each other, said reamer support moving means being operatively connected to said second clutch member, a cover for said core support carried by said supporting structure, a solenoid operatively connected to said follower, and means responsive to closing of said cover for energizing said solenoid to retract said follower and establish a driving connection between said clutch members.

'7. A core cleaning machine comprising a supporting structure including a core support, a reamer support mounted on said supporting structure for movement relative to said core support towards and away from a core carried by the latter, a reamer rotatably mounted on said reamer support for movement about an axis parallel to the direction of movement of the reamer support, means connected to the reamer for rotating the same, means connected to the reamer support for moving the same, drive means connected to said reamer rotating means and said reamer support moving means, clutch means including first and second relatively movable members, said drive means being operatively connected to said first member, cam means carried by one of said members, a retractible follower engaging with said cam means for selectively moving said clutch members out of driving engagement with each other, said reamer support moving means being operatively connected to said second clutch member, a movable cover for said core support carried by said supporting structure, a solenoid operatively connected to said follower, and means engageable with and responsive to closing of said cover for energizing said solenoid to retract said follower and establish a driving connection between said clutch members, a second cam means operatively connected to said second clutch member for selectively deenergizing said solenoid.

8. A core cleaning machine comprising a supporting structure including a core support, a reamer support mounted on said supporting structure for movement relative to said core support towards and away from a core carried by the latter, a reamer rotatably mounted on said reamer support for movement about an axis parallel to the direction of movement of the reamer support, means connected to the reamer for rotating the same, means connected to the reamer support for moving the same, drive means connected to said reamer rotating means and said reamer support moving means, a movable cover for said core support carried by said supporting structure, means engageable with and responsive to the closing of said cover for drivingly connecting said reamer support moving means to said driving means, abrading means reciprocably mounted on said cover, a bell crank carried by said supporting structure, means operatively connecting said bell crank to abrading means for reciprocatory movement in response to oscillation of said bell crank, and means operatively connecting said bell crank to said reamer support whereby said bell crank is oscillated in response to movement of said reamer support.

9. The combination of claim 8 wherein said means connecting said bell crank to said abrading means includes an arm pivotally attached to said cover and connected to said abrading means,

and a yoke on the end of said arm engageable with said bell crank.

ERNIE BYRON ESTERS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Re. 16,141 McDonough Aug. 11, 1925 667,880 Hinckley Feb. 12, 1901 1,010,657 Mason Dec. 5, 1911 1,203,844 Booth et a1. Nov. 7, 1916 1,259,494 Downer Mar. 19, 1918. 1,457,387 Neitzel June 5, 1923 1,577,478 Marburg Mar. 23, 1926 2,052,919 Brogdon et al Sept. 1, 1936 2,054,458 Arge et al. Sept. 15, 1936 2,161,115 Walstrom June 6, 1939 2,414,126 Sevin Jan. 14, 1947 2,426,028 Krueger Aug. 19, 1947 FOREIGN PATENTS Number Country Date 365,486 Germany Dec. 16, 1922 

